Systems and methods for shielding a hand sensor system in a steering wheel

ABSTRACT

Systems and methods of shielding a hand sensor system in a steering wheel are disclosed herein. An exemplary hand sensor system includes a sensor mat and a heater mat that is disposed between the sensor mat and a frame of the steering wheel. A power source selectively provides a heating current to the heater mat to provide heat to the steering wheel and a shielding voltage signal to the heater mat to provide electrical shielding for the sensor mat when heating is not needed or when sensing takes priority over heating. Alternatively, the system may include a shield mat that is separate from the heater mat and is disposed between the sensor mat and the heater mat. In addition, to isolate the signal carried by individual sensor return wires, a metallic or insulating covering or conduit may be provided around the wires or portions thereof.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/001,968 entitled “Systems and Methods for Shielding a Hand SensorSystem in a Steering Wheel”, filed May 22, 2014, the content of which isherein incorporated by reference in its entirety.

BACKGROUND

Current steering wheel designs may include a sensor mat disposed arounda rim of a steering wheel that detects presence of one or more hands onthe steering wheel rim. The sensor mat is disposed between an outer skinof the steering wheel and a rim of a steering wheel frame. The steeringwheel frame is typically made of metal, such as a magnesium alloy orsteel, and can be a source of interference for the electrical signal(s)in the sensor mat.

Accordingly, there is a need in the art for improved systems and methodsfor shielding a sensor system in a steering wheel.

BRIEF SUMMARY

Systems and methods of shielding a hand sensor system in a steeringwheel are disclosed herein. According to various implementations, thehand sensor system includes a sensor mat and a shield mat that isdisposed between the sensor mat and the frame of the steering wheel. Apower source is configured for providing a current to the shield mat,which prevents interference between the steering wheel frame and thesensor mat. A heater mat disposed around the steering wheel frame may beused as the shield mat by selectively generating a heating current forthe heater function or a voltage signal for the shield function of themat, or a separate heater mat and shield mat may be provided. Heatingcurrent levels may be between about 4 and about 8 amperes, aregenerated. Shielding current levels may be less than about 200microamperes. In certain implementations, separate power sources may beprovided to generate the heating current for heating and the voltagesignal for shielding, or one power source may selectively provide theheating current for heating and the voltage signal for shielding.

In addition, in implementations in which the sensor mat provides morethan one sensing zone, a sensor return wire from one sensing zone mayinterfere with a signal(s) carried by a sensor return wire from anadjacent sensing zone if the sensor return wires are too close. Toisolate the signals carried by individual sensor return wires, ametallic or insulating covering or dielectric or insulating conduit maybe provided around the wires or a portion thereof. By shielding thesensor mat properly, noisy or “shorted” measurements are prevented.

According to various implementations, a system for shielding a handsensor system in a steering wheel includes a sensor mat, a shield mat,and an electronic control unit. The sensor mat includes one or moresensing loops, and each of the sensing loops defines a sensing zone. Theshield mat is disposed between a steering wheel frame, and the shieldmat and includes one or more conductive loops. Each of the conductiveloops defines a conductive zone. The electronic control unit (ECU) is incommunication with the shield mat and includes a power source configuredfor generating a voltage signal configured for shielding one or moresensing zones of the sensor mat from interference from the steeringwheel frame.

The system may also include a heater mat disposed between the shield matand the steering wheel frame. In one implementation, the heater mat isin communication with the ECU, and the power source is configured forselectively generating a heating current for the heater mat for heatingthe steering wheel and the voltage signal for the shield mat forshielding one or more sensing zones. In other implementations, separatefirst and second power sources may be provided, wherein the first powersource is configured for generating the heating current for the heatermat and the second power source is configured for generating the voltagesignal for the shielding mat. The first and second power sources may beprovided in one ECU or in separate ECUs.

According to various other implementations, a system for shielding ahand sensor system in a steering wheel includes a sensor mat, a heatermat, and an electronic control unit. The sensor mat includes one or moresensing loops, and each of the sensing loops defines a sensing zone. Theheater mat is disposed between a steering wheel frame and the sensor matand includes one or more conductive loops. Each of the conductive loopsdefines a conductive zone. The electronic control unit is incommunication with the heater mat and includes a power source configuredfor selectively generating a heating current configured for heating atleast a portion of the steering wheel and a voltage signal configuredfor shielding the sensor mat from interference from the steering wheelframe. The heating current is greater than a shielding current.

In certain implementations, the one or more sensing loops may include afirst sensing loop and a second sensing loop. The first sensing loop isspaced apart from the second sensing loop. The one or more conductiveloops of the shield mat or combination shield/heater mat may include afirst conductive loop adjacent the first sensing loop and a secondconductive loop adjacent the second sensing loop for selectivelyshielding or heating one or more areas at a time.

According to certain implementations, the power source is configured forgenerating the heating current for the first conductive loop of theheater mat in response to receiving a first presence signal from thefirst sensing loop indicating presence of a hand or other body partadjacent he first sensing loop or for the second conductive loop of theheater mat in response to receiving a second presence signal from thesecond sensing loop indicating presence of a hand or other body partadjacent the second sensing loop. Alternatively, the power source may beconfigured for generating the heating current for at least one or moreof the conductive loops of the heater mat in response to receiving an onsignal for the heater mat.

In addition, the power source is further configured for generating theshielding voltage signal for the first or second conductive zone inresponse to receiving a signal (e.g., an override signal) indicatingthat sensing in the first or second sensing zone, respectively, takespriority over heating. The electronic control unit is also configuredfor ceasing to generate the heating current for the one or moreconductive loops of the heater mat in response to a temperature of arespective sensing zone reaching a set temperature. In addition, theelectronic control unit may be configured for alternately generating theheating current and the shielding voltage signal periodically, such asevery about 10 to about 50 milliseconds. The above describedimplementations may also include a metallic shield disposed around atleast a portion of one or more wires connected to the sensor mat. Themetallic shield is configured for substantially isolating an electricalsignal carried by the shielded wire from another wire adjacent theshielded wire. The metallic shield may extend around substantially allof the wire that extends from each sensing loop. Alternatively, themetallic shield may extend around the portion of the wire extending fromone sensing loop that crosses another sensing loop.

In addition, the system may also include a conduit comprising adielectric material. At least a portion of the wires extending from thesensor mat are disposed within the conduit. For example, the conduit mayinclude a first conduit for at least a portion of the first wire and asecond conduit for at least a portion of the second wire.

Other various implementations may include methods of shielding a handsensor system in a steering wheel. According to certain implementations,the hand sensor system includes a shield mat disposed between a steeringwheel frame and a sensor mat. The sensor mat includes one or moresensing loops, and each sensing loop defines a sensing zone and isconfigured for detecting input from a driver's hand adjacent thereto.The shield mat includes one or more conductive loops, and each of theconductive loops defines a conductive zone. The method includesproviding a voltage signal to at least one of the one or more conductiveloops of the shield mat to shield a portion of the sensor mat adjacentthe conductive zone from the steering wheel frame. A shielding currentmay be less than about 200 microamperes. In certain implementations, thehand sensor system further includes a heater mat, and the heater mat isdisposed between the frame and the shield mat. The method furtherincludes providing a heating current to the heater mat, such as betweenabout 4 and about 8 amperes.

According to other implementations, the hand sensor system includes aheater mat between a steering wheel frame and a sensor mat. The sensormat includes one or more sensing loops, and each sensing loop defines asensing zone and is configured for detecting input from a driver's handadjacent thereto. The heater mat includes one or more conductive loops,and each of the conductive loops defines a conductive zone. The methodincludes: (1) selectively providing a heating current to at least one ofthe one or more conductive loops of the heater mat to heat at least oneof the one or more conductive zones of the steering wheel; and (2)selectively providing a voltage signal to at least one of the one ormore conductive loops of the heater mat to shield a portion of thesensor mat adjacent the conductive zone from the steering wheel frame.The heating current is greater than a shielding current.

BRIEF DESCRIPTION OF THE DRAWINGS

The components in the drawings are not necessarily to scale relative toeach other. Like reference numerals designate corresponding partsthroughout the several views.

FIG. 1A illustrates a cross sectional view of layers in a steering wheelaccording to one implementation.

FIG. 1B illustrates a perspective view of a sensor mat layer, a shieldmat layer, and heater mat layer according to the implementation in FIG.1A.

FIG. 1C illustrates a schematic diagram of the steering wheel system ofFIGS. 1A and 1B.

FIG. 1D illustrates a schematic diagram of the steering wheel system ofFIGS. 1A and 1B according to an alternative implementation.

FIG. 1E illustrates a schematic diagram of the steering wheel system ofFIGS. 1A and 1B according to another implementation.

FIG. 2 illustrates a cross sectional view of layers in a steering wheelrim according to one implementation.

FIG. 3A illustrates a top view of the heater mat layer shown in FIG. 2.

FIG. 3B illustrates a top view of the sensor mat layer shown in FIG. 2.

FIG. 4 illustrates a schematic diagram of the steering wheel system ofFIG. 2.

FIG. 5 illustrates a top view of the sensor mat of FIG. 3B showing aschematic area of each zone and the sensor return wires from each loopassociated with each zone.

FIG. 6A illustrates a perspective view of a conduit shield around sensorfeed and return wires for one sensor loop according to oneimplementation.

FIG. 6B illustrates a perspective view of a conduit shield around thesensor feed and the sensor return wires for sensor loops 1 through naccording to one implementation.

FIG. 7 illustrates a perspective view of a metallic shield around asensor return wire according to one implementation.

FIG. 8 illustrates the metallic shield shown in FIG. 7 attached to asensor mat.

FIG. 9 illustrates a perspective view of a metallic shield around asensor return wire with a shield return wire connected to the metallicshield according to one implementation.

FIG. 10 illustrates the metallic shield shown in FIG. 9 wherein theshield return wire is soldered to the metallic shield.

FIG. 11 illustrates a perspective view of the heater mat shown in FIG.3A.

FIG. 12 illustrates a perspective view of a mesh shield mat layeraccording to one implementation.

FIG. 13 illustrates a perspective view of a mesh shield mat layeraccording to another implementation.

DETAILED DESCRIPTION

Systems and methods of shielding a hand sensor system in a steeringwheel are disclosed herein. According to various implementations, thehand sensor system includes a sensor mat and a shield mat that isdisposed between the sensor mat and a frame of the steering wheel. Apower source provides a voltage signal to the shield mat to provideelectrical shielding for the sensor mat. Interference with theelectrical signal(s) carried by the sensor mat may occur due to theproximity of the sensor mat to the steering wheel frame, which istypically metal, and providing the shielding voltage signal to theshield mat prevents this interference. In addition, the system may alsoinclude a heater mat. The heater mat may be separate from the shield mator it may be used as a combination heater and shielding mat. To use theheater mat as a shield mat, the power source generates a heating currentfor heating the steering wheel or the shielding voltage signal for usingthe heater mat as a shield mat. The heating current is greater than ashielding current.

FIG. 1A illustrates a cross section of a steering wheel rim thatincludes a frame 12, an over molded layer 14 around the frame 12, aheater mat layer 6 around the over molded layer 14, a shield mat layer 7around the heater mat layer 6, a sensor mat layer 8 around the shieldmat layer 7, and a skin 20 around the sensor mat 8. The frame 12 istypically a magnesium alloy, aluminum alloy, steel, or a combinationthereof, but it may be made of another suitable rigid material(s). Theover molded layer 14 is formed from a polyurethane foam or thermoplasticelastomeric foam, for example. The outer skin 20 is typically made ofleather or vinyl, but could also include wood, carbon fiber, plastic,polyurethane foam, fabrics, or any other suitable material. By keepingthe shield mat layer 7 directly adjacent the sensor mat layer 8, thedistance fluctuation between the two layers due to thermal expansion andcontraction is minimized. In addition, the distance between these layersis further minimized by the tension of the outer skin 20 squeezing thelayers together.

FIG. 1B illustrates a perspective view of the sensor mat 8, shield mat7, and heater mat 6 shown in FIG. 1A. The sensor mat 8 may include oneor more sensing zones, such as sensing zones 24 a, 24 b, 24 c, which aredesignated as zones 1-3 for example, that are distinct and spaced apartfrom each other, such as the sensor mats described in U.S. patentapplication Ser. No. 14/178,578, entitled Steering Wheel Hand DetectionSystems and filed Feb. 12, 2014, which is herein incorporated byreference in its entirety. In addition, the shield mat 7 and the heatermat 6 may include one or more conductive zones, such as conductive zones54 a, 54 b, 54 c and 52 a, 52 b, 52 c, respectively, which correspond tothe sensing zones on the sensor mat and which allow for selective zoneshielding and heating.

An electronic control unit (ECU) 30, which is shown in FIG. 1C, is inelectronic communication with the heater mat 6, the sensor mat 8, theshield mat 7, and one or more other vehicle systems (not shown). Inparticular, sensor return wires 34 a-34 c extend between the ECU 30 andeach sensing loop 24 a-24 c, respectively, and conductive feed wires 56a-56 c and 58 a-58 c extend between the ECU 30 and each conductive loop52 a-52 c and 54 a-54 c for the heater mat 6 and the shield mat 7,respectively. The ECU 30 includes a processor 31 and a power source 32.

The processor 31 is configured for detecting input from a driver, suchas presence of a hand, adjacent each sensing loop 24 a-24 c. In oneimplementation, an electrical signal from one or more sensing loops 24a-24 c is communicated to the processor 31, and the processor 31determines if the signal indicates input from the driver. For example,the signal may be generated through capacitance-type sensing, and theprocessor 31 may compare the generated signal with a range of signalsthat indicates presence of the driver's hand or other parts of thedriver's body.

In addition to being configured to detect presence of a hand or otherparts of the driver's body, the sensing loops 24 a, 24 b, 24 c and theprocessor 31 may also be configured to detect various types of userinput in each respective sensing zone, such as a grip, swipe motion, tapmotion, etc., from signals received from the sensor mat. For example, byusing a multi-zone sensor mat with the sensing loops disposed inspecific areas, the sensor mat may be configured for detecting when no,one, or both hands are on the steering wheel and/or when a knee istouching the steering wheel.

The power source 32 is configured for selectively generating anelectrical current through one or more conductive loops 52 a-52 c of theheater mat 6 for heating at least a portion of the outer skin 20 and avoltage signal through one or more conductive loops 54 a-54 c of theshield mat 7 for shielding at least a portion of the sensor mat 8 frominterference from the steering wheel frame 12. The heating current isgreater than a shielding current. For example, the heating current isaround 4 to around 8 amperes, which is sufficient for producing heat forheating the skin 20 of the steering wheel, and the shielding current isless than about 200 microamperes, which is sufficient for shielding thesensor mat 8 from the steering wheel frame 12, according to someimplementations. In certain implementations, for example, the shieldingcurrent may be between about 9 to about 11 microamperes. In oneparticular implementation, the heating current may be about 7 amperesand the shielding current may be around 10 microamperes. Theseelectrical current values may be per zone or per channel and are inputinto the ECU 30, according to certain implementations.

In one implementation (not shown), the ECU 30 may include at least afirst circuit and a second circuit between the power source 32 and theconductive loops 52 a-52 c and 54 a-54 c, respectively. The firstcircuit receives the heating current, which is a simple, resistivevoltage current, to heat the area adjacent the conductive loops 52 a-52c. The second circuit receives the shielding current, which may be afrequency-specific signal, for example, to shield the area adjacent theconductive loops 54 a-54 c. The frequency-specific signal of the secondcircuit is configured for matching, as close as possible, thecapacitance voltage signal generated for the sensing mat.

The level of heating current or shielding voltage signal to be generatedby the power source 32 and when the heating current or shielding voltagesignal is generated is changed is controlled by the processor 31,according to one implementation. For example, in variousimplementations, the processor 31 may be configured to instruct thepower source 32 to generate the heating current in one or moreconductive loops 52 a-52 c in response to receiving input from a button,switch, or other suitable input mechanism disposed on the steering wheelor elsewhere in the vehicle. In another implementation, the processor 31may be configured for generating the heating current in response toreceiving input from one or more sensing loops 24 a-24 c. For example,in a particular implementation, the processor 31 may be furtherconfigured to instruct the power source 32 to generate the heatingcurrent for a particular conductive loop(s) 52 a-52 c that is adjacentthe particular sensing loop(s) 24 a-24 c that senses the presence of thedriver's hand(s). This configuration allows the system to save energy byonly heating those portions of the steering wheel rim for which thepresence of the driver's hand is sensed. For example, if the processor31 senses the presence of the driver's hand adjacent sensing loop 24 a,the processor 31 may generate the heating current through the conductiveloop 52 a that is adjacent sensing loop 24 a to warm the portion of thesteering wheel under the driver's hand.

In another implementation, or in addition to the implementationdescribed above, the processor 31 may be configured for instructing thepower source 32 to generate the heating current until the earlier of thesteering wheel reaching a preset temperature or receiving an overridesignal from another vehicle system indicating that sensing in one ormore zones takes priority over heating. In particular, the processor 31may receive a temperature signal from one or more temperature sensors inthe steering wheel and determine from the temperature signal whether thepreset temperature has been reached. For example, a typical heaterregulation range can be anywhere from about 30° C. to about 42° C. Thetemperature is typically detected using one or more thermistors, such asa negative temperature coefficient (NTC) type thermistor, according tocertain implementations. The thermistor provides feedback to theprocessor 31, and the processor 31 uses the temperature feedback toregulate the target temperature on the steering wheel.

In addition, the override signal may indicate to the processor 31 thatanother system should receive electrical resources that would otherwisebe allocated to the heater mat 6 for the heater function or that inputfrom the sensor mat 8 takes priority over heating.

In another implementation, or in addition to the implementationdescribed above, the processor 31 may be configured for instructing thepower source 32 to alternate generation of the heating current and theshielding voltage signal periodically, such as alternating every about10 to about 50 milliseconds. In other implementations, the period may bebetween about 10 to about 100 milliseconds. The period of alternationmay be set based on the speed of the processor 31, the outside or insidetemperature, or the preferences of the driver, for example. In addition,on board temperature monitoring may affect the timing, such as toprevent overheating of the controller itself. Or, if a specific faultcondition is detected and the ECU 30 needs to prioritize managing thatfault condition, the timing may be affected.

In the alternative implementation shown in FIG. 1D, a first power source62A is provided for generating a heating current for the heater mat 6and a second power source 62B is provided for generating a shieldingvoltage signal for the shield mat 7. The first 62A and second powersources 62B are shown in FIG. 1D as being within two separate ECUs 60A,60B, respectively, but, alternatively, these may be included in one ECU60, as shown in FIG. 1E. These implementations allow the system toprovide for continuous shielding and heating when desired, for example.In addition, ECU 60A or 60 may include a first circuit for receiving theheating current from power source 62A, which is a simple, resistivevoltage current, to heat the area adjacent the conductive loops ofheater mat 6. And, ECU 60B or 60 may include a second circuit forreceiving the shielding voltage signal from power source 62B, which maybe a frequency-specific signal, for example, to shield the area adjacentthe conductive loops of shield mat 7.

Furthermore, in sensor mats having multiple zones, signals carried bysensor return wires associated with each sensing zone may generate noisein the sensing loops or sensor return wires associated with adjacentzones when the wires are too close to each other. This noise decreasesthe ability of the sensor mat to detect presence of a hand adjacent oneor more sensing zones. In addition, cross talk from a sensor return wirefrom one zone that crosses over another zone may result in unintendeddetection from another zone. Accordingly, various implementationsdescribed herein, such as the implementations described related to FIGS.5-10, provide for shielding around at least a portion of the sensorreturn wires that may be disposed adjacent another sensing zone orsensor return wire to isolate the signal(s) carried by the sensor returnwire(s).

As mentioned above, the heater mat may be configured for serving as aheater mat and a shield mat, according to various implementations. FIG.2 illustrates a cross sectional view of a steering wheel rim accordingto one such implementation. The steering wheel rim includes a steeringwheel frame 12, an over molded layer 14 disposed around the steeringwheel frame 12, a heater mat 16 disposed around the over molded layer14, a sensor mat 18 disposed around the heater mat 16, and an outer skin20 disposed over the sensor mat 18.

FIG. 3A illustrates the heater mat 16 according to one implementation.The heater mat 16 includes one or more conductive loops, such asconductive loops 22 a, 22 b, 22 c, and each loop 22 a, 22 b, 22 cdefines a conductive zone. The conductive loops 22 a, 22 b, 22 c arespaced apart on the surface of the heater mat 16.

FIG. 3B illustrates the sensor mat 18 according to one implementation.The sensor mat 18 includes one or more sensing loops, such as sensingloops 24 a, 24 b, 24 c, and each sensing loop 24 a, 24 b, 24 c defines asensing zone, such as zones 1, 2, and 3 shown in FIG. 1B and FIG. 5. Thesensing loops 24 a, 24 b, 24 c are spaced apart from each other on thesurface of the sensor mat 18. As shown in FIG. 3B, the sensing loops 24a-24 c may be capacitance type sensors. In addition, in otherimplementations, the sensor mat 18 may include one or more biometricsensors (e.g., sensing temperature, heart rate, etc.) or other suitabletype of sensor.

Furthermore, biometric type sensors may be disposed in the vehicle towork in conjunction with hand sensing through the steering wheel usingnon-biometric type sensors. These biometric sensors may be disposed onthe steering wheel or elsewhere in the vehicle. Examples of thesebiometric type sensors include retina detection, heart rate monitoring,arousal state monitoring, and driver detection (e.g., in a vehicleseat).

As shown in FIG. 4, the ECU 30 is in electronic communication with theheater mat 16, the sensor mat 18, and one or more other vehicle systems(not shown). In particular, the sensor return wires 34 a-34 c extendbetween the ECU 30 and each sensing loop 24 a-24 c and conductive feedwires 36 a-36 c from the heater mat 16 extend between the ECU 30 andeach conductive loop 22 a-22 c.

The power source 32 is configured for selectively generating a heatingcurrent through one or more conductive loops 22 a-22 c for heating atleast a portion of the outer skin 20 and a shielding voltage signalthrough one or more conductive loops 22 a-22 c for shielding at least aportion of the sensor mat 18 from interference from the steering wheelframe 12. The heating current is greater than a shielding current. Forexample, the heating current is around 4 to around 8 amperes, which issufficient for producing heat for heating the skin 20 of the steeringwheel rim, and the shielding current is less than around 200microamperes, which is sufficient for shielding the sensor mat 18 fromthe steering wheel frame 12. In a particular implementation, the heatingcurrent may be about 7 amperes and the shielding current may be betweenabout 9 and about 11 microamperes. And, in a specific implementation,the shielding current may be around 10 microamperes. These electricalcurrent values may be per zone or per channel and are input into the ECU30, according to certain implementations. Various implementations of howthe processor 31 determines which level of current to supply to theconductive loops 22 a-22 c are described above in relation to FIG. 1C.In addition, in an alternative implementation (not shown), the ECU 30may include separate first and second power sources, wherein the firstpower source is configured for generating a shielding voltage signal andthe second power source is configured for generating a heating current.Furthermore, ECU 30 may include a first circuit for receiving theheating current from power source 32, which is a simple, resistivevoltage current, to heat the area adjacent the conductive loops 22 a-22c. And, ECU 30 may include a second circuit for receiving the shieldingvoltage signal from power source 32, which may be a frequency-specificsignal, for example, to shield the area adjacent the conductive loops 22a-22 c.

FIG. 5 illustrates a schematic top view of the sensor mat 18 showing thepath of each of three sensor return wires 34 a, 34 b, 34 c extendingfrom their respective sensing loops 24 a, 24 b, 24 c. As shown, thesensor return wire 34 a extends over a portion of sensing loop 24 b,which may be a source for interference for sensing loop 24 b. To isolatethe signal carried by the sensor return wires from each other whileallowing for efficient routing of wires along the sensor mat 18, one ormore of the sensor return wires 34 a-34 c extending between the ECU 30and the sensing loops 24 a-24 c may include shielding around at least aportion of the sensor return wire 34 a-34 c. FIGS. 6A-10 illustratesvarious implementations of the wire shielding. Reference numeral 34 isused generally in these figures to refer to any sensor return wire thatextends from the sensor mat 18.

In particular, FIGS. 6A and 6B illustrate a conduit 38 that includes adielectric material. For example, the material may include nylon, PVC,polypropylene, or a metallic material. At least a portion of at leastone sensor return wire 34 is disposed within the conduit 38. Forexample, the conduit 38 may be disposed between a particular sensorreturn wire 34 and a portion of an adjacent sensing loop for which thesensor return wire 34 may cause interference, such as in the area ofpossible interference shown in FIG. 5. Alternatively, the conduit 38 maybe disposed around the portion of the sensor return wire 34 near thewire's connection to the sensor mat 18, around the portion of the sensorreturn wire 34 near the wire's connection to the ECU 30, or around allor most of the sensor return wire 34. One conduit may include a set ofwires associated with each zone or sets of wires associated withmultiple zones. FIG. 6A illustrates the conduit 38 having two wiresassociated with a single zone extending through it a sensor return wire34 that carries a signal from the single zone and a second, sensor feedwire that carries a signal to the zone. FIG. 6B illustrates the conduit38 having more than one set of wires extending through it, wherein eachset of two wires is associated with zones 1 through n and includes asensor feed wire and sensor return wire.

FIGS. 7 and 8 illustrate a metallic shield 37 around a portion of thesensor return wire 34. The metallic shield 37 is configured forsubstantially isolating an electrical signal carried by the shieldedwire. For example, the metallic shield 37 may be a metallic braidedconduit. For example, the material may include nylon, PVC,polypropylene, or a metallic material. As shown in FIG. 7, an insulatinglayer surrounds the sensor return wire 34, and the metallic shield 37surrounds the insulating layer. A protective sheathing may be disposedaround the metallic shield 37. The protective sheathing may include athin layer of a dielectric material such as polyamide, silicon rubber,and polyester. In other implementations, another conductive layer may beused instead of the metallic braid shown in FIGS. 7 and 8. Theprotective sheathing may include a thin layer of a dielectric materialsuch as polyamide, silicon rubber, and polyester.

FIGS. 9 and 10 illustrate another implementation in which a shieldreturn wire 40 is connected to the metallic shield 37 to further shieldthe sensor return wire 34 from interference. The shield return wire 40shown in FIG. 10 is soldered to the metallic shield 37, but othersuitable methods of attaching the shield return wire 40 to the metallicshield 37 may be used, such as, for example, crimping. The shield returnwire 40 is connected to the ECU 30, and the power source 32. generates acurrent through the shield wire 40, which provides a desirable referencefor preventing interference.

In addition, the metallic shield 37 shown in FIG. 7 or 9 and the conduit38 shown in FIG. 6A or 6B may be used separately or in combination toprovide sufficient shielding for the sensor return wires 34 extendingbetween each sensing loop 24 and the ECU 30.

In the implementation shown in FIG. 5, the metallic shield 37 may bedisposed around the portion of sensor return wire 34 a extending fromsensor loop 24 a that extends over sensing loop 24 b to isolate the twosensing zones from each other. However, in the implementation shown inFIG. 8, the metallic shield 37 is disposed around substantially all ofthe sensor return wire 34.

The shield mat layer 7 described above in relation to FIGS. 1B and 3Bmay include one or more conductive wires stitched onto a backing layer.However, in alternative implementations, the conductive wire(s) on theshield mat layer may be arranged and/or secured to the backing layerdifferently. For example, alternative implementations of a shield matlayer may include a knitted metallic mesh that forms a mesh shield matlayer. For example, FIG. 12 illustrates one implementation of a knittedmetallic mesh layer in which metallic threads 71 are knitted together ina weft knit pattern and are disposed on a backing layer 76 to form amesh shield mat layer 70. FIG. 13 illustrates another implementation ofa knitted metallic mesh layer in which metallic threads 81 are knittedtogether in a warp knit pattern and are disposed on backing layer 86 toform a mesh shield mat layer 80. The knit patterns shown in FIGS. 12 and13 allow the mesh shield mat layers 70, 80 to maintain contact whenstretched, which maintains electrical conductivity through the meshlayer 70, 80 after the layer 70, 80 is secured to the steering wheelrim. These knit patterns are exemplary, and other suitable knit patternsmay be used in other implementations.

In the exemplary layers 70, 80 shown in FIGS. 12 and 13, the spacingbetween adjacent courses and wales is between about 1 mil and about 4mils. In certain implementations, the spacing of adjacent courses andwales is about 2 mils. For example, the mesh may include 25 to 29courses per inch of length and have 14 to 15 openings per inch of width.In addition, the threads may comprise any suitable conductive materials,such as MONEL or copper, for example. In one implementation, the threadsare MONEL 400 wire.

Furthermore, the diameter of the threads may be selected to provide athickness of the mesh of between about 0.002 and about 0.005 inchesthick, according to some implementations. For example, the diameter ofthe threads may be around 0.0035 inches. The knitted meshes shown inFIGS. 12 and 13 are not coated with a dielectric material, but in otherimplementations, the knitted mesh may be coated with a suitabledielectric material.

The backing layers 76, 86 may include a foam material, for example, orother suitable material. The thickness of the backing layer 76, 86 maybe between about 1 mil and about 4 mils thick. For example, the backinglayer 76, 86 in certain implementations is about 2 mils thick.

In some implementations, the knitted mesh may be adhered to the backinglayer 76, 86, for example, using acrylic dispersion type adhesives orany other suitable type of adhesive. Alternatively (not shown), theknitted mesh may be sewn onto the backing layer 76, 86 or attached usingany suitable fastening mechanism.

The knitted mesh can stretch about 10% to about 15% along axis A-A oraxis B-B without interfering with the conductive properties of theknitted mesh, according to certain implementations. For theimplementation shown in FIG. 12, axis A-A extends parallel to long edges77 of the backing layer 76, and axis B-B extends perpendicularly to axisA-A and parallel to short edges 78 of the backing layer 76. The knittedmetallic mesh is disposed on the backing layer 76 such that the A-A axisextends through an uppermost point 91 of a first loop L1 in a firstcourse C1 and a first wale W1 and an uppermost point 92 of a second loopL2 in a second course C2 and a second wale W2, wherein the first courseC1 is below and adjacent to the second course C2 and the first wale W1is to the left of and adjacent the second wale W2. Axis B-B extendsthrough the uppermost point 92 of the second loop L2 in the secondcourse C2 and an uppermost point 93 of a third loop L3 in the first waleW1 and a third course C3 that is above and adjacent to the second courseC2.

Similarly, in the implementation shown in FIG. 13, the mesh is orientedsuch that axis A-A extends through a lower right contact point 95 and anupper left contact point 96 formed by overlapping threads in C1, W1.Axis B-B extends through a lower left contact point 97 and an upperright contact point 98 formed by overlapping threads C1, W1.

During installation of the mesh shield mat layer 70, 80 on the steeringwheel rim, the shield mat layer 70, 80 is stretched along the A-A axisand the B-B axis. This arrangement of the mesh layer improves contactbetween the adjacent loops.

Other implementations (not shown) may include a mesh shield mat layerthat includes metal strips that are welded together to form the meshmaterial. In certain implementations, the metal strips may be coatedwith a dielectric material. The welded mesh may have a stretchabilitythat is between about 5% and about 10%, according to someimplementations.

In certain implementations, the mesh shield mat layer 70, 80 may includeone mesh layer area that provides one conductive zone adjacent the meshlayer area. However, in other implementations (not shown), the meshshield mat layer 70, 80 may comprise a plurality of separate mesh layerareas that are spaced apart and separated from each other on the backinglayer 76, 86 but are electrically coupled together to provide oneconductive zone adjacent each of the plurality of mesh layer areas. Suchan implementation provides targeted shielding to a particular area ofthe steering wheel and reduces the amount of mesh layer used for themesh shield mat layer 70, 80. In another implementation (not shown), theplurality of separate mesh layer areas may not be electrically coupledand are instead coupled separately to the power source to provideseparate conductive zones that can be activated separately.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art. Methods and materials similar or equivalent to those describedherein can be used in the practice or testing of the present disclosure.As used in the specification, and in the appended claims, the singularforms “a,” “an,” “the” include plural referents unless the contextclearly dictates otherwise. The term “comprising” and variations thereofas used herein is used synonymously with the term “including” andvariations thereof and are open, non-limiting terms. Whileimplementations will be described for steering wheel hand detectionsystems, it will become evident to those skilled in the art that theimplementations are not limited thereto.

As utilized herein, the terms “approximately,” “about,” “substantially”,and similar terms are intended to have a broad meaning in harmony withthe common and accepted usage by those of ordinary skill in the art towhich the subject matter of this disclosure pertains. It should beunderstood by those of skill in the art who review this disclosure thatthese terms are intended to allow a description of certain featuresdescribed and claimed without restricting the scope of these features tothe precise numerical ranges provided. Accordingly, these terms shouldbe interpreted as indicating that insubstantial or inconsequentialmodifications or alterations of the subject matter described and claimedare considered to be within the scope of the invention as recited in theappended claims.

It should be noted that the term “exemplary” as used herein to describevarious embodiments is intended to indicate that such embodiments arepossible examples, representations, and/or illustrations of possibleembodiments (and such term is not intended to connote that suchembodiments are necessarily extraordinary or superlative examples).

The terms “coupled,” “connected,” and the like as used herein mean thejoining of two members directly or indirectly to one another. Suchjoining may be stationary (e.g., permanent) or moveable (e.g., removableor releasable). Such joining may be achieved with the two members or thetwo members and any additional intermediate members being integrallyformed as a single unitary body with one another or with the two membersor the two members and any additional intermediate members beingattached to one another.

References herein to the positions of elements (e.g., “top,” “bottom,”“above,” “below,” etc.) are merely used to describe the orientation ofvarious elements in the FIGURES. It should be noted that the orientationof various elements may differ according to other exemplary embodiments,and that such variations are intended to be encompassed by the presentdisclosure.

It is important to note that the construction and arrangement of thesensing system for a steering wheel as shown in the various exemplaryembodiments is illustrative only. Although only a few embodiments havebeen described in detail in this disclosure, those skilled in the artwho review this disclosure will readily appreciate that manymodifications are possible (e.g., variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters, mounting or layering arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter described herein. Forexample, elements shown as integrally formed may be constructed ofmultiple parts or elements, the position of elements may be reversed orotherwise varied, and the nature or number of discrete elements orpositions may be altered or varied. The order or sequence of any processor method steps may be varied or re-sequenced according to alternativeembodiments. Other substitutions, modifications, changes and omissionsmay also be made in the design, operating conditions and arrangement ofthe various exemplary embodiments without departing from the scope ofthe present embodiments.

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

1-8. (canceled)
 9. A system for shielding a hand sensor system in asteering wheel comprising: a sensor mat comprising one or more sensingloops, each of the sensing loops defining a sensing zone; a heater matdisposed between a steering wheel frame and the sensor mat, the heatermat comprising one or more conductive loops, each of the conductiveloops defining a conductive zone; and an electronic control unit incommunication with the heater mat, the electronic control unitcomprising a power generator configured for selectively generating afirst electrical current configured for heating at least a portion ofthe steering wheel and a second electrical current configured forshielding the sensor mat from interference from the steering wheelframe, the first electrical current being larger than the secondelectrical current.
 10. The system of claim 9 wherein: the one or moresensing loops comprises a first sensing loop and a second sensing loop,the first sensing loop being spaced apart from the second sensing loop,the one or more conductive loops comprises a first conductive loopadjacent the first sensing loop and a second conductive loop adjacentthe second sensing loop, the power generator is configured forgenerating the first electrical current for the first conductive loop ofthe heater mat in response to receiving a first presence signal from thefirst sensing loop indicating presence of a hand adjacent the firstsensing loop, and the power generator is configured for generating thefirst electrical current for the second conductive loop of the heatermat in response to receiving a second presence signal from the secondsensing loop indicating presence of a hand adjacent the second sensingloop.
 11. The system of claim 10, wherein the power generator is furtherconfigured for generating the second electrical current for the first orsecond conductive zone in response to receiving an override signalindicating that sensing in the first or second sensing zone,respectively, takes priority over heating.
 12. The system of claim 10,wherein the power generator is further configured for generating thesecond electrical current for the first conductive loop of the heatermat in response to a temperature of the first sensing zone reaching aset temperature and for generating the second electrical current for thesecond conductive loop of the heater mat in response to a temperature ofthe second sensing zone reaching a set temperature.
 13. The system ofclaim 9, wherein the power generator is configured for alternatelygenerating the first electrical current and the second electricalcurrent periodically.
 14. The system of claim 13, wherein the powergenerator is configured for alternately generating the first electricalcurrent for about 1 to about 2 seconds and the second electrical currentfor about 1 to about 2 seconds.
 15. The system of claim 9, wherein thefirst electrical current is between about 6 amperes and about 8 amperes.16. The system of claim 9, wherein the second electrical current is lessthan about 50 microamperes.
 17. The system of claim 9, furthercomprising a metallic shield disposed around at least a portion of oneor more wires connected to the sensor mat, the metallic shieldconfigured for substantially isolating an electrical signal carried bythe shielded wire from another wire adjacent the shielded wire.
 18. Thesystem of claim 17, wherein: the one or more sensing loops comprises afirst sensing loop and a second sensing loop, a first wire extends fromthe first sensing loop and a second wire extends from the second sensingloop and a portion of the second wire crosses over the first sensingloop; and the metallic shield extends around at least the portion of thesecond wire that crosses over the first sensing loop.
 19. The system ofclaim 18, wherein the metallic shield extends around substantially allof the second wire that extends from the second sensing loop.
 20. Thesystem of claim 19, further comprising a conduit comprising a dielectricmaterial, wherein at least a portion of the first or second wires aredisposed within the conduit.
 21. The system of claim 20, wherein theconduit comprises a first conduit for at least a portion of the firstwire and a second conduit for at least a portion of the second wire. 22.The system of claim 9, further comprising a conduit comprisingdielectric material, wherein at least a portion of one or more wiresconnected to each sensor loop are disposed within the conduit.
 23. Asystem for shielding a hand sensor system in a steering wheelcomprising: a sensor mat comprising one or more sensing loops, and eachof the sensing loops defines a sensing zone; a shield mat disposedbetween a steering wheel frame and the sensor mat, the shield matcomprising one or more conductive loops, each of the conductive loopsdefining a conductive zone, and an electronic control unit, theelectronic control unit being in communication with the shield mat andcomprising a power generator configured for generating an electricalcurrent configured for shielding the sensor mat from interference fromthe steering wheel frame. 24-25. (canceled)
 26. The system of claim 23,further comprising a heater mat disposed between the shield mat and thesteering wheel frame.
 27. The system of claim 26, wherein the electricalcurrent is a first electrical current, and the heater mat is incommunication with the electronic control unit, the power generatorconfigured for selectively generating a second electrical currentconfigured for heating the steering wheel. 28-29. (canceled)
 30. Thesystem of claim 26, wherein the electronic control unit is a firstelectronic control unit, the power generator is a first power generator,and the electrical current is a first electrical current, and the heatermat is in communication with a second electronic control unit comprisinga second power generator configured for generating a second electricalcurrent configured for heating the steering wheel, wherein the secondelectrical current is greater than the first electrical current. 31-32.(canceled)
 33. The system of claim 26, wherein: the power generator is afirst power generator, the electrical current is a first electricalcurrent, and the electronic control unit further comprises a secondpower generator configured for generating a second electrical current,and the heater mat is in communication with the electronic control unitand the second electrical current is configured for heating the heatermat, the second electrical current being higher than the firstelectrical current.
 34. The system of claim 26, wherein: the powergenerator is a first power generator, the electrical current is a firstelectrical current, and the electronic control unit is a firstelectronic control unit, the system further comprises a secondelectronic control unit, the second electronic control unit comprising asecond power generator configured for generating a second electricalcurrent, the heater mat being in communication with the secondelectronic control unit and the second electrical current beingconfigured for heating the heater mat, the second electrical currentbeing higher than the first electrical current. 35-38. (canceled)